The present invention relates to an apparatus for measuring magnetic characteristics of materials and more particularly to a magnetic characteristic measuring apparatus that can measure magnetic susceptibility of biomagnetic characteristics with a very high sensitivity.
Various methods and apparatuses for measuring magnetic characteristics have been proposed in the past. For example, the Faraday method is a method for measuring magnetic characteristics of a specimen using the magnitude of a drive current applied to a dynamic system to dynamically balance the magnetic force that acts on the specimen placed within a certain magnetic field. A specimen oscillation method utilizes a design such that when a specimen mounted on a moving coil is oscillated in a certain magnetic field, current induced in the moving coil is influenced by magnetic characteristics of the specimen. An apparatus shown in FIG. 8 measures magnetic characteristics of a specimen 19 by applying alternating magnetic fields to the specimen 19 mounted at the tip of a quartz rod 18 to oscillate the specimen 19, and by converting the oscillation by an electrostrictive element 20 mounted at the bottom of the quartz rod 18 to analyze the oscillation.
However, the aforementioned Faraday method or the specimen oscillation method have a limited measuring sensitivity due to magnetic noise caused by ripple and switching noise of a power source since the magnetic field is applied during measuring. Moreover, it has been difficult to enhance the sensitivity of the measuring apparatus shown in FIG. 8 due to the influence of magnetic noise as well as to being limited by the characteristics of the electrostrictive element that converts amplitudes to electrical signals.